Press control apparatus

ABSTRACT

Control apparatus and circuitry for controlling the movement of a press ram or the like including a main electrical connector means having pairs of contact terminals between which are to be connected normally open and normally closed manually operable switch means for operating the press ram or for stopping the same. The main connector means are also provided with another pair of contact terminals which, to permit operation thereof, must be externally short circuited. A connector duplicating unit in some cases also forming an operator control station unit including at least a normally closed manually operable switch is provided having input electrical connector means which may be removably connected to the main electrical connector means and at least one output electrical connector means which duplicates the main electrical connector means. The connector duplicating unit is wired to connect in series circuit relation each manually operable switch of the operator control station unit forming a part thereof and the similar switches of one or more other operator control station unit which may be connected to the one or more output electrical connector means thereof. The circuit of the connector duplicating unit must be completed by the connection to each output electrical connector means of circuit completing means including input electrical connector means removably secured to the output electrical connector means involved. Such circuit completing means may be a terminal operator control station unit or dummy unit not requiring other units to be connected thereto or another combination connector duplicating and operating control station unit requiring such other unit. Any operator control station unit having a normally open switch means is provided with short circuit means for short circuiting the aforementioned other pair of contact terminals of the main electric connector means and any dummy unit or operator control station unit having only normally closed switch means is devoid of any short circuit connections for the aforesaid other pair of contact terminals so that the mistaken connection of such a dummy unit or operator control station unit into the main electrical connector means cannot effect the operation of the press control circuit.

United States Patent [4 1 May 30,1972

Luenser [54] PRESS CONTROL APPARATUS [72] Inventor: Kurt K. Luenser,Desota, Tex.

[73] Assignee: Verson Allsteel Press Company, Chicago,

Ill.

[22] Filed: Mar. 22, 1971 [21] Appl. No.: 126,809

[52] 1.1.8. CL... .307/112, 340/147 MT [51] Int. Cl ..Fl6p 3/04 [58]Field of Search ..340/l47 R, 147 MT, 147 B, 147 CN;

235/l5l.l1; 307/112, 113

[56] References Cited UNITED STATES PATENTS 2,905,838 9/1959 King et a1..307/l 12 Primary Exatniner H. 0. Jones Assistant Examiner-.William J.Smith Attorney-Wallenstein, Spangenberg, Hattis & Sprampel [57] ABSTRACTControl apparatus and circuitry for controlling the movement of a pressram or the like including a main electrical connector means having pairsof contact terminals between which are to be connected normally open andnormally closed manually operable switch means for operating the pressram or for stopping the same. The main connector means are also providedwith another pair of contact terminals which, to permit operationthereof, must be externally short circuited. A connector duplicatingunit in some cases also forming an operator control station unitincluding at least a normally closed manually operable switch isprovided having input electrical connector means which may be removablyconnected to the main electrical connector means and at least one outputelectrical connector means which duplicates the main electricalconnector means. The connector duplicating unit is wired to connect inseries circuit relation each manually operable switch of the operatorcontrol station unit forming a part thereof and the similar switches ofone or more other operator control station unit which may be connectedto the one or more output electrical connector means thereof. Thecircuit of the connector duplicating unit must be completed by theconnection to each output electrical connector means of circuitcompleting means including input electrical connector means removablysecured to the output electrical connector means involved. Such circuitcompleting means may be a ter minal operator control station unit ordummy unit not requiring other units to be connected thereto or anothercombination connector duplicating and operating control station unitrequiring such other unit. Any operator control station unit having anormally open switch means is provided with short circuit means forshort circuiting the aforementioned other pair of contact terminals ofthe main electric connector means and any dummy unit or operator controlstation unit having only nonnally closed switch means is devoid of anyshort circuit connections for the aforesaid other pair of contactterminals so that the mistaken connection of such'a dummy unit oroperator control station unit into themain electrical connector meanscannot efiect the operation of the press control circuit.

12 Claims, 11 Drawing Figures Patented May 30, 1972 5 Sheets-Sheet 2INVENY'OR Kan-r K, LUENSER Patented May 30, 1972 5 Sheets-Sheet 1 /zzA23 4 HZY 1 L-LJ\L \J lnvawrom M/Rr K. LUENSER MIMM A'r-rvs.

PRESS CONTROL APPARATUS The present invention relates to machinecontrols, and more particularly to a new and improved control systemhaving the most useful application in metal stamping presses and thelike where the presses may be controlled by a number of differentoperators from individual control stations.

It is customary in metal stamping presses of this type to provide acontinuous mode of operation where the press ram is continuouslyoperated, a single cycle mode of operation where the press ram is undermanual control only during the down stroke of the ram and the ramautomatically comes to rest in the raised position thereof each cycle,and an inch mode of operation where the movement of the press ram isconstantly under the control of a press operator at all times. Inpresses of great tonnage capacity, a number of operators are commonlystationed about the machine and for safety reasons and each operator hashis own operator control station with control which, together with run"controls of the other stations must generally be operated to operate thepress when a single cycle or inch mode of operation is desired.Generally, each operator station has a pair of run push buttons whichmust be operated to initiate these modes of operation. For safetyreasons, each operator should be able to stop the press by depression ofonly one stop" push button.

When a metal stamping press is manufactured and sold to a particularcustomer, the control circuit for the press has generally been made toaccommodate a certain fixed number of operator control stations, some ofwhich may be designed to have only stop" push buttons and others ofwhich have both stop and run" push buttons. The stop push buttonsgenerally operate normally closed switches in the press control circuitwhich are connected in series so that the depression of any stop pushbutton will de-energize the press control circuit immediately to stopthe movement of the press ram. Each run push button may operate two ormore normally open switches and at least one normally closed switch. Onegroup of corresponding normally open switches controlled by the run pushbuttons are generally connected in series circuit relation in theenergization circuit of the main control devices which are usuallyclutch control relays controlling clutch solenoids so that all of thecontrol push buttons must be operated to energize the control device.Similarly, another group of normally closed switches controlled by therun" push buttons are commonly connected in series circuit relation tode-energize a control relay when any control push button is depressedalthough in the preferred exemplary form of the invention these switchesare connected in parallel.

\ Operator control stations are sometimes supplied in the form ofindividual plug-in units which plug into corresponding receptacles inthe originally manufactured machine. The contact terminals of the plugsand receptacles involved were generally wired to accommodate theparticular type of operator control station unit involved. The metalstamping press sold to aparticular customer, therefore, would beinitially provided with the proper number of receptacles wired toreceive the particular operator control station plug-in units ordered bythe customer. If the customer initially desired to have only twooperator control station units of particular type, and he subsequentlydesired to add additional operator control stations it was necessary torewire the press control circuit and to add additional receptacles toaccommodate additional operator control station plug-in units.

The present invention provides a new concept for press controls in thatthe basic control circuit of the press is wired to only a single mainreceptacle seemingly to accommodate only a single operator controlstation having both run and "stop" push buttons with the exception that,i in the most advantageous form of the invention, an additional pair ofcontact terminals are provided in the receptacle connected to a part ofthe press control circuit to be interrupted for stopping the pressramwhich pair of contact terminals must be bridged by an external jumperconnection to permit operation of the press. In accordance with thepresent invention, a unique combination of different plug-in units orthe like are provided for insertion into the aforementioned mainreceptacle (to be sometimes referred to as a main electrical connectormeans) which combination of plug-in units permit the selective use ofone or more operator control station plug-in units of the typecomprising only stop" push buttons and associated switches, or of thetype comprising both stop push buttons and "run" push buttons and theirassociated switches with a machine having only one receptacle or thelike as described. Thus, although the initially manufactured press isseemingly constructed to operate with only one operator controlstation,it nevertheless has the flexibility of receiving any number ofoperator control stations of the types referred to without any change inthe wiring or number of receptacles of the originally manufacturedpress.

One of the basic plug-in units insertable into the main receptacle ofthe press will be referred to as a connector duplicating unit which is aunit which duplicates the main connector means at least one and, in somecases, two or more times. (Such duplicated connector means will besometimes referred to as output electrical connector means.) ln'one formof the invention, the connector duplication unit is also an operatorcontrol station unit which includes stop. push buttons only andassociated switches or both stop" and run" push buttons and associatedswitches. The one or more output electrical connector means provided ina connector duplicating unit are designed removably to receive thecomplementary output electrical connector means of one or more unitsforming what will be referred to as circuit completing means. Withoutthe connection of circuit completing means to an output electricalconnector means of a connector duplicating unit, electrical continuitycannot be established between all contact terminals of the inputconnector means of a connector duplicating unit The circuit completingmeans for an output electrical connector means of a connectorduplicating unit may be only one other unit referred to as a terminalcircuit completing unit which can be an operator control station unit orwhat will be referred to as a dummy unit including all of the circuitconnections for completing the circuit connected to the input electricalconnector means thereof, or may constitute another connector duplicatingunit requiring other circuit completing means to complete the circuitryinvolved. When a connector duplicating unit also constitutes an operatorcontrol station unit, each of the switches forming apart thereof isconnected between corresponding contact terminals of the input andoutput electrical connector means. When all output elecrrical connectorsof all connector duplicating units have connected thereto the electricalconnector means of circuit completing means as described, allcorresponding switches of the various operator control station unitsinvolved to be connected in series will be so connected between thevarious pairs of contact terminals of the main electrical connectormeans of the press described above.

The aforementioned dummy unit and an operator control station unit whichis not also a connector duplicating unit and having only stop pushbuttons controlling normally closed switches could create a serioushazard if the input electrical connector means thereof is inserted intothe main electrical connector means of the press since such units onlyhave terminal short circuiting switches or jumpers in the absence of theaforesaid additional pair of contact terminals of the main connectormeans. Such operator control station units and dummy units are notprovided with jumpers for interconnecting said additional pair ofcontact terminals. However, operator control station units having runpush buttons controlling normally open switches which must be closed inorder to complete energization circuits to the control devices of thepress control circuit are provided with such jumpers to providecontinuity of the press control circuit whenever such a unit is insertedinto the system ahead of an operator control station unit or dummy unitdevoid of such jumpers.

The flexibility of the press control system as described has resulted ina substantial simplification and lower cost of the basic press controlequipment and in greater convenience and lower cost to the customer whodesires to modify the number or type of operation control stations usedwith a particular press.

The above and other advantages and features of the invention will becomeapparent upon making reference to the specification to follow, theclaims and the drawings wherein:

FIG. 1 is an elevational view of a typical metal stamping press with anexposed receptacle for receiving the input plugin connector of anoperator control station unit;

FIG. 2 is a greatly enlarged view of a portion of the press shown inFIG. 1, showing one form of operator control station unit inserted intothe main receptacle thereof;

FIG. 3 is a view of a portion of the press shown-in FIG. 1 with acombination connector duplicating and operator control station unitplugged into the main receptacle of FIG. 1 and which combination unithas a circuit completing dummy unit inserted therein; I

FIG. 3A is a circuit diagram of the press control circuit for the pressof FIG. 1 with the combination connector duplicating and operatorcontrol station unit and circuit completing dummy unit shown in FIG. 3incorporated therein;

FIG. 4 is a view of a portion of the press shown in FIG. 1 with acombination connector duplicating and operator control station unitinserted into the main receptacle of the press shown in FIG. 1 with anadditional combination connector duplicating and operator controlstation unit and dummy unit electrically connected to the outputreceptacle of the former combination connector duplicating and operatorcontrol station unit;

FIG. 4A shown the circuit diagram of the various units shown in FIG. 4;

FIG. 5 is a view of a portion of the press shown in FIG. 1 with aconnector duplicating unit inserted into the main receptacle shown inFIG. 1 and having a pair of output receptacles into which are connecteddifferent types of operator control station units forming three operatorcontrol stations;

FIG. 5A shows the circuit diagram of the various units shown in FIG. 5;

FIG. 6 is an across-the-line diagram of the basic press control circuitcommon to all of the different forms of the invention illustrated in thepreceding figures.

FIG. 7 is a chart indicating the conditions of the various relays shownin FIGS. 3A, 4A, 5A and 6 at various angular positions of the press ramcrank arm; and

FIG. 8 is a timing diagram illustrating the operation of machinecontrolled cam switches shown in the circuit of FIGS. 2A, 3A, 4A, 5A and6.

Referring now to FIG. 1, a press is shown which is of the type disclosedin the David C. Verson and Albert Clements U.S. Pat. No. 2,286,943 withcertain modifications which are dictated by the present invention. Thepress 20 includes a frame 22 having a crown 24, a bed 26 and areciprocable ram 28 movable in gibs 30. In the press crown is mounted amotor (not shown), a flywheel 32 driven by the motor and connectedthrough a clutch 34, a clutch and brake assembly 36 and suitable gearing38, to a pair of large gears 40 which drive an eccentric 42 for pitman44 connected to the ram 28.

The clutch 34 and clutch brake assembly 36 may be of the pressure fluidoperated type (either hydraulic or pneumatic), and, in such case, thesupply of fluid thereto is under the control of one or more solenoidoperated valves, the solenoid or solenoids of which are incorporated inthe control circuit to be described.

On the frame 22 is a main or master control station 59 including acontrol panel 60 which has a manually operable function control meansillustrated as a control knob 61 (FIG.

2) which is movable to a number of different active stable and closedwhen the control knob 61 is in its various positions to accomplish theaforementioned inch, single cycle and continuous cycle modes ofoperation. The neutral" positions are positions which are inoperativepositions to minimize the possibility of inadvertent movement of thecontrol knob 61 into an undesired operating position from anotheroperating position when the control knob is moved one position from theoperative single," inch or continuous" positions. Thus, for example, ifthe control knob 61 were in its single" position, inadvertent movementof the control switch one position counterclockwise rather than oneposition clockwise to the off position would not result in the systembeing adjusted for an inch" mode of operation. As previously indicated,a continuous mode of operation is where the press ram is continuouslyoperated, a single cycle mode of operation is where the press ram isunder manual control only during the down stroke of the ram and the ramautomatically comes to rest in the raised position thereof each cycle,and an inch mode of operation is where the movement of the press ram isconstantly under the control of a press operator at all times. Inpresses of great tonnage capacity, a number of operators are oftenstationed about the machine and for safety reasons each operator has hisown operator control station run push buttons (like PB-2 and PB-3 inFIG. 2) with controls which, together with the run" push buttons of theother stations, must be operated to operate the press when a singlecycle or continuous mode of operation is desired. Generally, eachoperator control station has a pair of run" push buttons so that anaccidental pushing of only one run" push button will have no effect.Also, operation of the press in a continuous mode of operation requiresthe control knob to be moved into its continuous position, the rotationof a key switch by the rotation of a proper key into a member KS on thecontrol panel 60 and the momentary depression of a continuous reset pushbutton PB-4 on the control panel 60 along with operation of all "run"push buttons at all operator control stations for a give period. For theinch mode of operation, the control knob 61 is moved into its inchposition, and the spring urged control knob TS on the control panel 60is held in an inch" position while a push button PB-S is depressed.

In addition to the control panel 60, the master operator control station59 will include an operator control station unit like plug-in unit 63,63a or 63a shown in FIGS. 2, 3, 4, and 5 including a stop push buttonPB-l, a pair of the aforesaid run" push buttons PB-2 and PB-3 and anindicating lamp 69. FIG. 1 shows only a main receptacle 62 above thecontrol panel 60 into which receptacle can be operably inserted theinput plug connector 71 (sometimes referred to also as an inputelectrical connector means) of any of the operator control stationplug-in units 63,63a, 63a or 63a, or a plug-in unit 70 shown in FIG. 5(It should be understood that although the exemplary form of theinvention utilizes plug-in" units meaning that they have inputconnectors with male contact terminals insertable into the femalecontact terminals or sockets of receptacles, the present invention isequally applicable to units using input connectors with female contactterminals.)

FIG. 2 illustrates the insertion into the main receptacle of the inputplug connector 71 of the plug-in unit 63 which is to be referred to as aterminal operator control station plug-in unit because it acts as afinal or terminating circuit completing unit for the circuit into whichit is directly connected (unlike the other operator control stationunits 63a, 63a and 63a") which require the insertion into an outputreceptacle 73 thereof of another plug-in unit to complete the circuitryinvolved. The illustrated operator control station plug-in unit 63 (aswell as the other operator control station plug-in units) have sideflanges 65-65 through which may be extended anchoring screws 67 forphysically anchoring the same to the frame 22. (Obviously other means ofmounting these plug-in units may be provided.) The press controlapparatus illustrated in FIG. 2 is provided only with one operatorcontrol station, namely the master operator control station 59 fromwhich the entire press is controlled. Only one such operator controlstation would be used for relatively small presses where the owner ofthe press desires to minimize overhead by minimizing the number ofoperators necessary to operate the press. The energization of anindicating lamp 69 of any plug-in unit informs the operator thatoperating voltage is applied to the plug-in unit so that operation ofthe controls thereof should be effective in performing this intendedfunction. The stop and run push buttons operate pairs of contacts orswitches to be described which are respectively operable to terminatemovement of the press ram 28 and to initiate movement of the press ram28. As will be described, the run" push buttons contact may include bothnormally open and normally closed pairs of contacts. Corresponding pairsof normally open contacts of the different run push buttons in the presscontrol circuit to be described are connected in series so that theinadvertant pressing of only one of the run push buttons will not resultin the operation of the press ram 28. The provision of a terminaloperator control station plug-in unit like the unit 63 just described isnot per se novel. One of the important novel aspects of the invention isthe provision of special plugin units like the aforesaid plug-in units63 or 63a, 63a" and 70 which enable the addition of any desired numberof opera torcontrol station plug-in units from the single mainreceptacle 62.

In accordance with one of the features of the present invention,toenable the connection of any desired number of operator control stationto the main receptacle 62, there is provided a connector duplicatingunit, such as the combination connector and operator control stationplug-in units 630 in FIG. 3 or the plug-in unit 70 shown in FIG. 5. Theplug-in unit 63a has a input plug connector 71 insertable into the mainreceptacle 62, and an output'receptacle 73 (sometimes referred to as anoutput electrical connector means) which duplicates the main receptacle62 on the press frame 22. The combination connector duplicating andcontrol station plug-in unit 63a has the same basic controls as theterminal operator control station plug-in unit 63 shown in FIG. 2,namely a stop push button PB-l and a pair of run" push buttons PB-2 andPB-3 in addition to an indicating lamp 69. The push buttons PB-l, PB-2and PB-3 control contacts or switches of the same type previouslyreferred to in connection with the operator control station plug-in unit63. As it will be described in more detail hereinafter, the input plugconnector 71 and the output receptacle 73 have corresponding contactterminals whichare in- 'terconnected by conductors and contacts orswitches within the plug-in unit 630. The circuits involved havingseries connected contacts or switches which require for their completioncircuit completing means to be connected to the plug-in unit 63a by aplug connector inserted into the output receptacle 73, such as the inputplug connector 71 of a dummy plugin unit 75 shown in FIG. 3. The dummyplug-in unit 75 contains only jumper interconnections associated withcontacts or switches to be connected in series with various pairs ofcontact terminals of the output receptacle 73.

Refer now to FIG. 4 which illustrates the manner in which additionaloperator control stations can be added to the single operator controlstation of FIG. 3. As shown in FIG. 4, the dummy plug-in unit 75 in FIG.3 is replaced by a combination connector duplicating and operatorcontrol station unit 63a which is identical to the plug-in unit 630(corresponding parts thereof being similarly numbered), except that theplug connector of 71 thereof plugs into the output receptacle 73 of theplug-in unit 63a connected to a long cable 76 so that the plugin unit63a can be located a substantial distance from the plug-in unit 630,such as at the opposite side of the press frame 22. The wiring betweenthe contact terminals of the input plug connector 71 and the outputreceptacle 73 of the plug-in units 63a and 63a and the input plugconnector 71 of the dummy plug-in unit 75 connects the various contactsor switches to be connected in series of the plug-in units 630 and 63aand the various contacts or switches to be connected in parallelrespectively in series and parallel between various pair of contactterminals of the main receptacle. Thus the combination connectorduplicating and operator control station plug-in unit 63a and the dummyplug-in unit 75 together form a circuit completing means for thecombination connector duplicating and control station plug-in unit 63a.

FIG. 5 illustrates another form of the invention wherein theaforementioned connector duplicating unit 70 which plugs directly intothe main receptacle 62 performs the function of providing outputreceptacles 73a and 73b which are duplicates of main receptacle 62 andwiring which connects in series and parallel circuit relating allcontacts or switches to be connected respectively in series and parallelof the operator control station plug-in units 63, 63a and 63a" to beconnected to the output receptacle 73a and 73b. The input plug connector71 of the previously described combination connector duplicating andcontrol station plug-in unit 630 located on the right side of the frame22 is shown removably inserted within the output receptacle 73a of theconnector duplicating unit 70 and the input plug connector 71 of theterminal operator control station plug-in unit 63a located on the leftside of the frame 22 is removably inserted into the output receptacle73b of the connector duplicating unit 70. A third operator station isprovided by the operator control station plug-in unit 63a" located tothe rear of the right side of the frame 22. The operator control stationplug-in unit 63a" has only a "stop". push button for stopping the pressram, and, like the terminal operator control station plug-in unit 63,acts as a terminal circuit completing unit since it has no outputreceptacle. In addition to the contacts or switches controlled by thestop push button PB-l of the operator control station plug-in unit 63a",the plug-in unit 63a" has jumpers interconnecting the various contactterminals of the output receptacle 73 of the plug-in unit 63a associatedwith contacts or switches of the plug-in unit 63a to be connected inseries.

Refer now FIG. 3A which shown a schematic diagram of the circuit formedby the combination connector duplicating and control station plug-inunit 63a, the dummy unit 75 and the basic press control circuit which isconnected to the main receptacle 62 of the press. As shown in FIG. 3A,the input plug connector 71 has 16 male contact terminals which areinsertable within 16 female or socket contact terminals of the mainreceptacle 62 or other similar receptacles. The output receptacle 73 ofthe plug-in unit 63a has sixteen female contact terminals. For thepurpose of simplifying the training of the circuits, the sixteen contactterminals of each input plug connector and the output receptacle hasbeen divided into two groups of eight contact terminals eachrespectively numbered as contact terminals Nos. 1 through 8 and 1'through 8'. Each pair of correspondingly numbered terminal contact pairsl 1', 22, or 3-3, etc. in a contact terminal pair associated with thesame circuit portion and across which contacts or switches, lamps or ajumper are to be connected. Contact terminal pairs 1-1, 22,etc., of mainreceptacle 62 extend to respective pairs of juncture points in the mainpress control circuit to be described, which juncture points are to beinterconnected or disconnected to effect various relay control functionsto be described. In a connector duplicating unit like the combinationconnector duplicating and operator control station plug-in unit 63a,contact or switches which are to be connected in series across a pair ofjuncture points in the press control circuit are shown connected inseries between one of the correspondingly numbered contact terminals ofthe input plug connector 71 and the output receptacle 73. A conductorextends between the other correspondingly numbered and primed contactterminals of the input plug connector and output receptacle involved, sothat continuity between a correspondingly numbered pair of contactterminals of the main receptacle 62 associated with contacts or switchesto be connected in series cannot be effected unless circuit completingmeans, like the dummy plug-in unit 75 or other terminal plugin unit, isinserted or coupled to each output receptacle 73 involved. (Contacts orswitches or lamps connected in parallel do not need circuit completingmeans to effect switch continuity.)

All input plug connectors 71 and output receptacles 73 of the variousunits described are respectively identical and each plug connector 71 isinsertable into an output receptacle 73 or the main receptacle 62 inonly one position where the corresponding contact terminals are inengagement.

As previously indicated, any terminal circuit completing unit like dummyplug unit 75 containing only jumper connections or operator controlstation plug-in unit 63a" containing only jumper and normally closedcontacts or switches completing continuity of circuits having seriesconnected contacts or switches could create a dangerous condition ifsuch a plug-in unit were inadvertently plugged directly into the mainreceptacle 62, since then all circuits would have continuity which arenecessary to initiate. operation of the press ram. To prevent such adangerous condition, the press control circuit to be described isprovided with a pair of juncture points which must be connected bycontinuous jumper in order to effect operation of the press ram ,thesejuncture points extend to contact terminals 2 and 2' of the mainreceptacle 62. Any operator control station plug-in unit which hasnormally opened contacts or switches is provided with a jumper 78 whichprovides continuity between the Nos. 2 and 2 contact terminals of theinput plug connector thereof, and any terminal plug-in circuitcompleting unit like the dummy plug-in unit 75 and operator controlstation plug-in unit 63a" devoid of any normally open contact orswitches has no connections between its Nos. 2 and 2' contact terminalsof the input plug connector 71 thereof. f

As shown in FIG. 3A, the stop push button of combination connectorduplicating and operator control station plugin unit 630 operate amovable contact 81 which normally bridges a pair of normally-closedcontact 79. A conductor 88 extends between the right contact of the pairof contacts 79 and the No. 1 contact terminal of the input plugconnector 71, and a conductor 90 extends between the left contact of thepair of contacts 79 and the N0. 1 contact terminal of the outputreceptacle 73. A conductor 88 extends between the No. 1' contactterminal of the output receptacle 73 and the No. 1' contact terminal ofthe input plug connector 71. Contact terminals 1 and 1' of the outputreceptacle 73 thus must be bridged by circuit completing connectionsmaking external connection with the output receptacle 73 to thenormally? closed contacts 79 effective. The depression of the stop pushbutton PB-l will then disconnect normally-closed contacts 79 tointerrupt the press control circuit to stop the press ram. Any of theother operator control station plug-in unit connected to the the outputreceptacle 73 will connect corresponding normally-closed stop contacts79 in series with the contacts 79 of the plug-in unit 63a. I

The "run push button PB-2 of the plug-in unit63a has a movable contact83 which normally interconnects a normallyclosedpair of contacts 80 andthe run push button PB-3 has a movable contact 83 which normallyinterconnects a normally-closed pair of contacts 80'. The contacts 80and 80 are connected in series between the No. 4 contact terminals ofthe input plug connector 71 and the output receptacle 73 by conductor 92extending between the No. 4 contact terminal of the input plug connector71 and the left hand terminal of the pair of contact 80, a conductor 94extending between the right hand contact of the pair of contacts 80 andthe left hand contact of the pair of contacts and a conductor 96extending between the right contact of the pair of contacts 80' and theNo. 4 contact terminal of the output receptacle 73. A conductor 92'extends between the No. 4' contact terminals of the output receptacle 73and the input plug connector 71.

Depression of the run push buttons PB-2 and PB-3 respectfully result inthe disconnection of the pair of contacts 1 80 and 80' and theinterconnection of a pair of normally-open contact 82 and 82'respectively by the movable contacts 83 and 83'. The normally-open pairsof contacts 82 and 82 are connected in series between the Nos. 6 contactterminals of the input plug connector 71 and the output receptacle 73 bya conductor 98 connected between the No. 6 contact terminal of the inputplug connector 71 and the left contacts of the pair of contacts 82, aconductor 99 extending between the right contact of the pair of contacts82 and the left contact of the pair of contacts 82', and a conductor 101extending between the right contact of the pair of contacts 82' and theNo. 6 contact terminal of the output receptacle 73. A conductor 98extends between the Nos. 6 contact terminals of the output receptacle 73and the input plug connector 71.

The run push buttons PB-2 and PB-3 have respectively movable contactsand 85' which normally interconnect normally-closed pair of contact 84and 84' respectively. These pair of normally-closed contacts 84 and 84'are connected in parallel with one another. A conductor 102 extendsbetween the right contact of the pair of contacts 84 and the rightcontact of the pair of contacts'84', and a conductor 104 extends betweenthe left contact of the pair of contacts 84 and the left contact of thepair of contacts 84'. The parallel connected pairs of contacts 84' and84 are connected directly across the Nos. 5 and 5' contact terminal ofthe input connector 71 by conductor extending between the No. 5 contactterminal of the input plug connector 71 and the left contact of the pairof contacts 84, and a conductor 100' extending between the right contactof the pair of contacts 84' and the No. 5 contact terminal of the inputplug connector 71. The parallel connected pairs of contacts 84 and 84'are respectively connected across the Nos. 5 and 5' contact terminals ofthe output receptacle 73 by conductor 103' extending between the rightcontact of the pair of contacts 84 and the No. 5 contact terminal of theoutput receptacle 73, and be a conductor 103 extending from the leftcontact of the pair of contacts 84' and the No. 5 contact of the outputreceptacle 73. k

When the push buttons PB-2 and PB-3 are depressed, the movable contacts85 and 85 leave the pairs of normally closed contacts 84 and 84' andmake connection across pairs of normally-open contacts 86 and 86'. Thepairs of normallyopen contacts 86 and 86' are connected in seriesbetween the No. 7 contact terminals of the input plug connector 71 andthe output receptacle 73 by a conductor 108 extending between the No. 7contact terminal of the input plug connector 71 and the left contact ofthe pair of contacts 86, a conductor 110 extending between the rightcontact of the pair of contacts 86 and the left contact of the pair ofcontacts 86', and a conductor 1 12 extending between the right contactof the pair of contacts 86' and the No. 7 contact terminal of the outputreceptacle 73. A conductor 108' extends between the No. 7' contactterminals of the output receptacle 73 and the input plug connector 71.

The indicating lamp 69 is connected across the Nos. 3 and 3 contactterminals of the input plug connector 71 by a pair of connectors 114 and114' respectively, and the lamp 69 is connected to the Nos. 3 and 3'contact terminals of the output receptacle 73 receptacle 73 byconductors 1 16 and 116', respectively. A

The dummy plug unit 75 contains jumpers 120, 122, 124, 126 respectivelyconnected between the contact pairs 1-1', 44', 66, and 7--7' of theinput plug connector 71 of the dummy plug-in unit 75 and thus establishfinal connections between the various pairs of series connected pairs ofpush button contacts. As previously explained, pairs of contacts, lampsor jumpers in the other plug-in units to be connected in parallel do nothave any jumpers in the dummy plug-in unit 75 to complete connectionsbetween the same.

As previously indicated, in FIG. 4 there is shown an additionalcombination connector duplicating and operator control station unit 63ahaving an input plug connector 71 which extends into the outputreceptacle 73 of the other combina' tion connector duplicating andoperator control station plugin unit 630 connected directly to theoutput receptacle 62. Theseplug-in units 630 and 63a' are identical andso a further description on the wiring of the plug-in unit 63a need notbe given. It is apparent that the insertion of the input plug connector71 of the plug-in unit 634' into the output receptacle 73 of the plug-inunit 63a connects the normally-closed contacts 80' and 80 of both ofthese plug-in units in series between the No. 4 contact terminals of themain receptacle 62 and the output receptacle 73 of the plug-in unit 63a,connects the pairs of normally-open tenninal 82 and 82' of the pluginunits 63a and 63a in series between the No.6 contact terminals of themain receptacle 62 and the output receptacle 73 of the plug-in unit 63a,connects the normally-closed pairs of contacts 84 and 84' of the plug-inunits 630 and 63a in parallel across the Nos. and 5' contact terminalsof the main receptacle 62, connects the normally-open pairs of contacts86 and 86 of the plug-in units 630 and 63a between the No. 7 contactterminals of the main receptacle 62 and the output receptacle 73 of theplug-in unit 63a, connects the normally-closed pairs of contacts 79 ofthe plug-in units 63a and 63a between the No. 1 contact terminals of themain receptacle 62 and the output receptacle 73 of the plug-in unit 63a,connects the indicating lamps 69 of the plug-in units 63a and 63a" inparallel with the indicating lamp 69 of plug-in unit 63a, and connectsthe normally-closed pair of contacts 84 and 84 of the plug-in unit 63ain parallel with the correspondingly numbered contacts of the plug-inunit 63a. The jumper connections made by the dummy plug-in unit 75plugged into the output receptacle 73 of the plug-in unit 630' efi'ectthe same circuit connections as the dummy plug-in unit 75 in theembodimentof FIG. 3.

Referring now to FIG. 5A which shows the circuit diagram for thearrangement of plug-in units shown in FIG. 5, which includes the samecombination connector duplicating and operator control station unit 630shown in FIG. 4 and so a further description of the wiring of this unitwill not now be given. The operator control station unit 63a" whichplugs into the output receptacle 73 of the plug-in 63a includes only'anindicating lamp v69, and a single stop" push button PB-l and relatednormally-closed switch contacts and wiring and jumpers to be describedfor completing various circuits having contacts connected in series ofone another. Accordingly, the "stop" push button PB-l operates a movablecontact 81 which normally interconnects a pair of normally-closedcontacts 79 which are respectively connected by conductors 88 and 88"between the No. 1 and No. 1' contact terminals of the input plugconnector 71 of the plug-in unit 63a". The indicating lamp 69 isconnected by conductors 1 14 and v1 14' respectfully between the Nos. 3and 3' contact terminals of the input plug connector 71. Jumpers122,124, and 125 respectively interconnect the Nos. 4 and 4', 6 and 6,and 7 and 7 contact terminals of the input connector 71 in the samemanner and for the 7 same purpose served by correspondingly numberedjumpers of the dummy plug-in unit 75 previously described. As in thecase of dummy plug-in unit 75 which only has circuit element or circuitsdealing with normally-energized circuits, the plug-in unit 63a" isdevoid of any jumpers between the Nos. 2 and 2' contact terminals of theinput connector 71 thereof.

It is thus apparent that the indicating lamps 69 of theplug-in unit 63aand 63a" are connected in parallel across the Nos. 3 and 3' contactterminals of the input plug connector 71 of the plug-in unit 63a andthat the pair of normally-closed contacts 79 of the plug-in units 63a"and 63a are connected in series across from Nos. 1 and 1' contactterminals of the input plug connector 71 of the plug-in unit 63a. Also,the other normallyopen and normally-closed pairs of contacts associatedwith the run" push buttons PB-2 and PB-3 of the plug-in unit 63a areconnected in the same manner across the various associated contactterminals of the input. plug connector 71 of the plug-in unit 63a as inthe case of the plug-in unit 63a described in connection with FIG. 3A.

As previously indicated, the input connector 71 of the plugin unit 63ais inserted into the output receptacle 73a of the connector duplicatingplug-in unit 70, and the input plug connector 71 of the terminaloperator control station plug-in unit 63 is inserted into the outputreceptacle 73b of the connector duplicating plug-in unit 70. The plug-inunit 70 connects all corresponding circuit elements to be connected inparallel, like lamp 69 and contacts 84 and 84, in parallel circuitrelation,and all corresponding contacts to be connected in series, likecontacts 80 and 80' 82 and 82', and 86 and 86',in series circuitrelation across the associated similarly numbered pairs of contactterminals of the input plug connector 71 of the plug-in unit 70. To thisend, a conductor 121 extends between the No. 1 contact terminal of theoutput receptacle 73a and the No. 1 contact terminal of the outputreceptacle 73b of the plug-in unit 70. The No. 1 contact terminal of theoutput receptacle 73b is connected by a conductor 88" to a rightterminal of a pair of normally-closed contacts 79 associated with thestop" push button PEP-1 of the plug-in unit 63. The left contact of thepair of contacts 79 is connected by a conductor 88 to the No. 1 contactterminal of the input plug connector 71 of the plug-in unit 63. Aconductor 123 extend between the No. 1 contact terminal of the outputreceptacle of the plug-in unit 70 and the No. 1 contact terminal of theinput plug connector 71' thereof. Similarly, a a conductor 123' extendsbetween the No. 1' contact terminal of the output receptacle 73a and theNo. 1' contact terminal of the input plug connector 71' of the-plug-inunit 70, thereby to connect the various normally-closed contacts of thevarious plug-in units in series circuit relation between the Nos. 1 and1' contact terminals of the input plug connector 71'.

A conductor 125 extends between the No. 3 contact terminals of theoutput receptacles 73a and 73b, and a conductor 125' extends between theNo. 3' contact terminals of the output receptacles 73a and 73b thus toconnect the terminals associated with the various indicating lamps 69 inparallel. Conductors 127 and 127' respectively extend between the Nos. 3and 3' contact terminals of the input plug connector 71' and saidconductors 125 and 125', respectively, and also to the oppositeterminals of an indicating lamp 69 for the plug-in unit 70. The terminaloperator control station plug-in unit 63 has an indicating lamp 69connected by conductors 114 and 1 14' to the Nos. 3 and 3 contactterminals of the input plug connector 71 thereof, so that the lastmentioned indicating lamp 69 is connected in parallel with all the otherindicating lamps 69 and 69 across the Nos. 3 and 3' contact terminals ofthe input plug connector 71' of the plug-in unit 70.

A conductor 128 extends between the No. 4 contact terminal of the outputreceptacle 73a and the No. 4' contact terminal of the output receptacle73b. A conductor 92" extends between the No. 4' contact terminal of theinput connector 71 of the plug-in unit 63 and the right contact of thenormallyclosed pair of contacts 80 associated with the run" push buttonPB-3 of the plug-in unit 63. The pair of contacts 80' are connected inseries with the other corresponding pair of normally-closed contacts 80associated with the other run push button PB-2 by conductor 94 extendingbetween the left contact of the pair of contacts 80' and the rightcontact of the pair of contacts 80. A conductor 92 extends between theleft contact of the pair of contacts 80 and the No. 4 contact terminalof the associated input plug connector 71. A conductor 129 extendsbetween the No. 4 contact terminal of the output receptacle 73b and theNo. 4 contact terminal of the input plug connector 71'. Similarly, aconductor 129' extends between the No. 4' contact terminals of theoutput receptacle 73a and the input plug connector 71'. Thus, contacts80 and 80' associated with the various run" push buttons PB-2 and PB-3of all the various operator control station plug-in units are connectedin series across the Nos. 4 and 4 contact terminals of the input plugconnector 71'.

A conductor 100 extends between the No. 5 contact terminal of the inputplug connector 71 and the left contact of a pair of normally-closedcontacts 84 initially interconnected by the movable contact operated bythe run push button PB-2. A conductor 102 extends between the rightcontact of the pair of contacts 84 and the left contact of the pair ofcontacts 84' interconnected by the movable contact 85 operated by therun push button PB-3. A conductor connects the left contact of the pairof contacts 84 to the No. 5' contact temiinal of the input plugconnector 71, thereby to connect the pairs of contacts 84 across theNos. 5 and 5' contact terminals of the input plug connector 71. Aconductor 104 connects the right contact of the pair of contacts 84' tothe left contact of the pair ofcontacts 84 thereby to connect the pairof contacts 84 in parallel with the pair of contacts 84.

A conductor 130 extends between the No. 6 contact terminal of the outputreceptacle 73a and the No. 6' contact terminal of the output receptacle73b. A conductor 98" extends between the No. 6' contact terminal of theinput plug connector 71 of the plug-in unit 63 and the right contact ofthe pair of normally-open contacts 82 associated with the "run" pushbutton PB-3 of the plug-in unit 63. A conductor 99 connects thenormally-open contacts 82 and a pair of contacts 82 of the ?run" pushbutton PB-2 in series with one another, and a conductor 98 connects thepair of normally-open contacts 82 to the No. 6 contact ten-ninal of theinput plug connector 71.

A conductor 135 extends between the No. 6 contactof the outputreceptacle 73b and the No. 6 contact terminal of the input plugconnector 71'. Similarly, a conductor 135' extends between the No. 6'contact terminal of output receptacle 73a and the No. 6' contactterminal of the plug connector 71, thereby to connect all of the variousnormally-open pairs of runlpush button contacts 82 and 82" of thevarious plug-in units 63, 63a and 63a" in series across the Nos. 6 and6' contact terminals of the input plug connector 71' of the plug-in unit70. I Conductors 136 and 136 respectively extend between the Nos. 5 and5' contact terminals of the output receptacles 73a and 73b andconductors 138 and 138 respectively extend between theconductors 136 and136' to the Nos. 5 and 5' contact terminals of the input plug connector71', thereby connecting all of the various normally-closed run" pushbutton contacts'84 and 84' in parallel across the Nos. 5 and 5 contactterminals of the'input plug connector 71'.

A'conductor 140 extends between the No.7 contact terminal of the outputreceptacle 73a and the No. 7' contact terminal of the output receptacle73b of the plug-in unit 70. A conductor 108" extends between the No. 7'contact terminal of the input plug connector 71 of the plug-in unit 63and the right contact of the pair of normally-open contacts 86'associated with .run push button PB-3. A conductor 110 connectsthe pairof contacts 86' in series with a pair of normally opencontacts 86 of therun, push button PB-2. A conductor 108 connects the left contact of thepair of contacts 86 with the No. 7 contact terminal of theassociatedinput plug connector 71. A conductor 148 connects the No. 7contact terminal of the output receptacle 73b to the No. 7 contactterminal of the input plug connector 71' of the plug-in unit 70. Aconductor 146' extends between the No. 7' contact terminal of the outputreceptacle 73a and the No. 7' contact terminal of the input plugconnector 71', to connect the various normally-open contacts 86 and 86'of the various plug-in units 63 and 63a between the Nos. 7 and 7 contactterminals of the input plug connector 71 As in the case of the otherplug-in units having normallyopen switches therein, a jumper 78 extendsbetween the Nos. 2 and 2' contact terminals of the input plug connector71 of the plug-in unit 63. Conductors 150 and 150' respectively extendbetween the Nos. 2 and 2 contact terminals of the output receptacles 73aand 73b, and conductors 152 and 152' respec tively extend between theNos. 2 and 2 contact terminals of the input plug connector 71 and theaforementioned conductors 150 and 150', thereby to connect the variousjumpers of the plug-in units in parallel with the Nos. 2 and 2' contactterminals of the input plug connectors 71 Refer now to FIG. 6 whichshown an across-the-line diagram showing the press control circuit inwhich the various contacts and indicating lamps of the two operatorcontrol station plug-in units 63 and 63a of FIGS. 4 and 4A. The contactterminals of the main receptacle 62 are also identified in FIG. 6. Asource 160 of AC voltage is provided having one terminal grounded andanother terminal connected to the movable wiper 162' of a six positionswitch 162 operated by the function switch control knob 61. The wiper162" couples the source of AC voltage to a conductor 164 in all but the"off" position of the control knob 61. The conductor 164is coupledthrough the normally-closed "stop" push button contacts 79 to one end ofthe primary winding 166a of a transformer 166. The other end of thewinding 166a is grounded. The transformer 166 has a center tappedsecondary winding 166k. Short circuit current-responsive switch means168a is connected between the center tap point of the secondary winding166b and ground. Similar short circuit current-responsive switch means16% and 1680 are positioned respectively in the connections between theends of the secondary winding 166b and the power buses L1 and L2. Theshort circuit currentresponsive switch means 168a, 168b and 168:- aredesigned so that when any of these switch means receives a short circuitcurrent or a current above a given desired limit, that switch means andall the other short circuit current-responsive switch means willautomatically open. (Such a ganged relationship of switch means is wellknown in-the art and thus a description of the construction of same willnot here be given.) The presence of any ground connection within thevarious circuit branches to be described results in the flow of shortcircuit current in either the left or right half of the secondarywinding 166b, resulting in the complete de-coupling of the power busesL1 and L2 from the ground or any source of voltage.

Power bus L1 is connected to a parallel circuitof a switch 61-1 (whichis closed when function control knob 61 is in its single cycle position)and continuous operation switches 6l-2 and kS--l which are closedrespectively when the function control knob 61 and key operated memberKS are operated to their continuous? mode operating positions. Switches61-1 and 61-2 corresponding to switches 611 and 61-2 are connected inparallel positioned between main power buses L2 and secondary power busL2. The switches 61-1, kS-1 and 61-2 are connected through the aforesaidjumpers 78 and secondary power bus Ll. Various branches are connectedbetween opposite power buses which include an anti-repeat relay AR amanual controlled relay Y and a pair of clutch relays CR and CR.

The manual controlled relay Y has normally-closed contacts Y-3 and Y-3'in circuit branches 170-3 and 170-4. so that the clutch relays CR and CRcan be initially energized only when relay Y is de-energized, andnormally-open contacts Y] and Y--2 in a circuit branch 170-2 to controlthe initial energization of the anti-repeat relay AR so that theanti-repeat relay AR cannot be reset to an initially energized conditionat the end of each press cycle unless the manual controlled relay isenergized. (Contacts of relays are identified by the same designation asthe relay controlling the same and the normal condition thereof is thecondition when the associated relay is de energized.) 1 a i The seriesconnected normally-closed run" push button contacts 84 and 84 areconnected in parallel with one another and in series with the manualcontrolled relay Y in circuit branch 170-1 so that all the run controlpush buttons PB-2 and PB-S must be depressed to de-energize the manualcontrolled relay Y.

A portion of the circuit branch 170-2 which controls the initialenergization of the anti-repeat relay AR includes a series circuit ofswitch 169 (closed by depression of the continuous reset push buttonP54) in parallel with switch 61-5 (closed by depression of functioncontrol knob 61), normally-open contacts Y-l of the manual controlledrelay Y, the series connected normally-closed run push button contactsand 80, normally-closed contacts CR-l of the clutch relay CR andnormally-open contacts Y-2 of the manual controlled relay Y. A set ofnormally-open holding contacts AR-l of the anti-repeat relay AR areconnected between the bus L1 and the terminal of the contacts Y-2 remotefrom the bus Ll The latter terminal of the contacts Y-2 is connectedthrough a normallyclosed cam controlled switch CS-l to one terminal ofthe antirepeat relay AR whose opposite terminal is connected to the busL2. The cam switch CS-l, as shown in the timing diagram of FIG. 8, isopened momentarily when the arm driving the press ram is in a position,such as a 270 position, where the ram is nearing the return to itsinitial starting position. It is assumed that a crank arm drives thepress ram between its starting and work producing positions and that,when the ram is at the top of its path of travel the crank arm is in aposition. The crank arm rotates in a clockwise direction as viewed inFIG. 8, to first bring the press ram down to its bottommost position,which is the 180 position of the crank arm, and then rotates back to itsinitial starting position as it moves between the 180 and 360 positions.

Thus,when the manual controlled relay Y is energized and the press ramis in its uppermost position, an energization path for the anti-repeatrelay AR is established provided none of the run control push buttonsPB-2, PB-3, PB-2' and PB-3 are depressed, whereupon the relay willlock-in through the normally-open holding contacts AR-l of theanti-repeat relay.

The portion of the circuit branch 170-3 which elfects initialenergization of the clutch relay CR includes, in the order named,normally-open contacts AR-2 of the anti-repeat relay AR connected to busL1, the series connected normally-open run push button contacts 82 and82 and normally-closed contact Y-3 of the manual controlled relay Yconnected to relay Y which is connected to main bus L2. It is thusapparent that upon depression of all of the run control push buttonsPB-2 and PB-3 and the continued energization of the anti-repeat relay ARthe manual controlled relay Y is de-ene'rgized and the clutch relay CRwill be energized through the circuit branch 170-3. The portion of thecircuit branch 170-4 which efiects initial energization of the clutchrelay CR includes, in the order named, the normally-open run push buttoncontacts 86 and 86' connected to the bus L2, nonnally-closed contactsY-3'- of .the manual controlled relay Y, normally-open contacts AR-Z ofthefanti-repeat relay AR connected to the relay CR. The clutch relays CRand CR connected to bus Ll becomes de-energized when any of the runcontrol push buttons PB-2 or PIS-3 are released before the ram reachesits lower most position, to stop the movement of thepress ram. However,once the crank arm of the press ram moves into an angular positionbetween 180 and 360 where a dangerous condition to the worker no longerexists,machine controlled cam switches CS-2 and CS-2 connectedrespectively in series with the normally-opened, contacts CR-2 and CR-Z'of the clutch relays CR and CR close to establish holding circuits whichenergizes the clutch relays CR and CR independently of the position ofthe aforementioned run control push button contacts until the camswitches CS-Z or CS-2' open when the press ram returns to its uppermostposition. The cam switches CS-2 and CS-Zare respectively shunted byseries circuits of the continuous function switch contacts 61-3 and61-3, and normally-closed contacts AR-4 and AR-4 of the anti-repeatrelay AR so that the holding circuits of relays CR and CR remainenergized for the continuous mode of operation.

Thus, when the function control knob 61 is moved to its continuous"position to effect a continuous cycle mode of operation of the press, tocomplete the initiation of a continuous cycle of operation all of therun control push buttons PB-2 and PB-3 must be continuously depresseduntil the ram reached its lowermost position where the cam switches CS-Zand CS-2' close to energize the holding circuits of the relays CR andCR. The continuous cycle function switch contacts 61-3 do not becomeeffective to energize the clutch relay continuously until theanti-repeat relay is de-energizedtoclose the normally-closed contactAR-4 and AR-4 respectively in series with the contacts 61-3 and 61-3.The clutch relays CR and CR becomes de-energized near the end of anoperating cycle when the cam switch CS-l opens whereupon clutch relaysCR and CR will be locked-in an energized state which maintains thenormally-closed contacts CR-l open to keep the anti-repeat relay ARcontinuously in its de-energized state.

The press ram operation is controlled by solenoid S1 and S1 both ofwhich must be energized to operate the press ram. Solenoid S1 isconnected in series with normally-open contacts CR3 of clutch relay CRacross clutch relay CR, and

solenoid S1 is connected in series with normally-open contacts CR-3 ofclutch relay CR across relay CR. A motor 171 continuously drives aninput shaft of clutch 34 (FIG. 1) and is operative to drive the pressram when the clutch is engaged by the simultaneous energization ofsolenoids S1 and S1 upon energization of both clutch relays CR and CR.

The side of the clutch relay CR remote from the main bus L1 is connectedto the main bus L2 during the inch mode of operation by a branchincluding normally-open contacts which are closed by the push buttonPB-S, normally-open contacts TS-l' which are closed when the controlknob TS is turned to its inch position, and the contacts 61-4 which areclosed only when the function control knob 61 is in the inch" position.Similarly, the side of the clutch relay CR remote from the bus L2 isconnected to the bus Ll through a branch including normally-opencontacts 169 which are closed by depression of the push button PB-S,normally-open contacts TS-l which are closed when the contact knob TS isturned to its inch" position, and contacts 61-4 which are closed whenthe knob 61 is in its inch position. Thus, an inching operation can beobtained independently of whether the motor 169 is rotated simply bymoving the'function control knob 61 to the inch" position thereof andsimultaneously depressing the push buttons PB-S and turning the controlknob TS to the inch position. (The purpose of the control knob TS andthe associated contacts TS-l', TS-2 is to prevent the inadvertentoperation of the press ram when the function switch control knob is inits inch position if somebody should inadvertently, without knowing it,lean against the inch" push button PB-S.)

The press control circuit shown in FIG. 6 and just described may beincorporated with additional safety features, if desired, like thoseshown in FIG. 15 in copending application Ser. No. 876,672 filed Nov.14, 1969. The application also disclosed exemplary means by which thesimultaneous energization of solenoid S1 and S1 are effective inoperating the clutch 34.

It should be understood that the particular details of the press controlcircuit shown in FIG. 6 form .no part of the present invention and thuscan be vary widely from the circuit shown in FIG. 6. As previouslyindicated, the present invention deals with the wiring of the mainreceptacle 62 and the construction and wiring of the various plug-inunits described above insertable into or coupled to the main pressreceptacle which gives it flexibility in the number and type of operatorcontrol station useable with a simplified basic control system.

I claim:

1. In a machine which has a work producing portion movable by anoperating drive means from a remote starting position, where an operatoris relatively safe, to a work producing position where it can injure anoperator in the vicinity thereof, and is then movable back to saidstarting position, said machine including main electrical connectormeans including at least a first pair of contact terminals to beinterconnected by manually operable switch means of an operator controlstation, the opening or closing of the circuit across said pair ofcontact terminals resulting in either the energization of deenergization of said operating drive means, the improvement comprising:a first connector duplication unit for enabling selectively theinstallation of one or more operator control stations including manuallyoperable switch means to be connected in series between said first pairof contact terminals of said main connector means, said first connectorduplicating unit including first electrical connector meanscomplementary and removably connected to said main electrical connectormeans of the machine, and second electrical connector means forremovably receiving complementary electrical connector means of circuitcompleting means; a first operator control station having manuallyoperable switch means; and circuit completing means including firstelectrical connector means complementary and removably connected to saidsecond electrical connector means of said first connector duplicationunit; said first connector duplicating unit and said circuit completingmeans including circuit forming means for connecting said manuallyoperable switch means of said first operator control station and anysimilar manually operable switch means which may be present in saidcircuit completing means in series between said first pair of contactterminals of said main electrical connector means.

2. The machine of claim 1 wherein at least part of said circuitcompleting means includes a second operator station with manuallyoperable switch means connected in series with said manually operableswitch means of said first operator control station.

3. The machine of claim 1 wherein said first connector duplicating unitincludes, as an integral part thereof, said first operator controlstation including said manually operable switch means.

4. The machine of claims 1 wherein said first circuit completing meansis a terminal circuit completing unit providing a continuous circuitconnected in series with said manually operable switch means of saidoperator control station.

5. The machine of claim 1 wherein said first connector duplicating unitincludes third electrical connector means for removably receivingcomplementary electrical connector means of a circuit completing means,said first operator control station forming a separate unit having firstelectrical connector means complementary and removably connected to saidthird electrical connector means of said first connector duplicatingunit, said manually operable switch means of said first operator controlstation being electrically connected through said first electricalconnector means thereof to said circuit-forming means of said firstconnector duplicating unit.

6. The machine of claim 2 wherein said second operator control stationfonn part of said circuit completing means and constitutes a connectorduplicating unit by including second electrical connector means forremovably receiving complementary electrical connector means associatedwith a terminal circuit completing unit and a terminal circuitcompleting unit forming part of said circuit completing means and havingassociated electrical connector means complementary and removablyconnected to said second electrical connector means of said secondoperator control station,and circuit forming means in said terminalcircuit completing unit and second operator control station completingconnections which connect said manually operable switch means of saidfirst and second operator control stations in series between said pairor contact terminals of said main electrical connector means.

7. In a machine which has a work producing portion movable by anoperating drive means from a remote starting position, where an operatoris relatively safe, to a work producing position where it can injure anoperator in the vicinity thereof, and is then movable back to saidstarting position, said machine including main electrical connectormeans for removably receiving complementary connector means of anexternal circuit completing means and including at least a first pair ofcontact terminals to be interconnected by manually operable switch meansof an operator control station, the opening or closing of a circuitacross said pair of contact terminals resulting in the energization ordeenergization of said operating drive means, the improvementcomprising: a first connector duplicating unit for enabling selectivelythe installation of a number of operator control stations respectivelyincluding manually operable switch means to be connected in seriesbetween said first pair of contact terminals of said main electricalconnector means, said first connector duplicating unit including firstelectrical connector means removably connected to said main electricalconnector means and having a first pair of contact terminal engagingsaid first pair of contact terminals of said main electrical connectormeans, and second electrical connector means for removably receivingcomplementary electrical connector means of circuit completing meanswhich provides a continuous interconnection between said first pair ofcontact terminals of said second electrical connector means of the firstconnector duplicating unit or an operator control which has manuallyoperable switch means to be connected between said first pair of contactterminals of said second electrical connector means of said firstconnector duplicating unit; a first operator control station includingmanually operable switch means having one terminal connected to one ofsaid first electrical connector means of said first connectorduplicating unit, means connecting the other terminal of said manuallyoperable switch means of said first operator control station to one ofsaid pair of contact terminals of said second electrical connector meansof said first connector duplicating unit, means within said firstconnector duplicating unit which connects the other of said pair ofcontact terminals of said second electrical connector means of saidfirst connector duplicating unit to the other contact terminal of saidfirst pairof contact terminals of said first electrical connector meansof said first connector duplicating unit; and circuit completing meanshaving electrical connector means with a pair of contact terminalsremovably connected to said pair of contact terminals of said secondelectrical connector means of said first connector duplicating unit andcircuit completing means connected to said pair of contact terminals ofsaid electrical connectormeans thereof for completing a circuit whichconnects said manually operable switch means of said first operatorcontrol station across said first pair of terminals of said mainelectrical connector means.

8. In a machine which has a work producing portion movable by drivemeans from a remote starting position, where an operator is relativelysafe, to a work producing position where it can injure an operator inthe vicinity thereof; and is-then movable back to said startingposition, said machine including main connector means for removablyreceiving complementary connector means of an external circuitcompleting means and including at least a first pair of contactterminals to be interconnected by normally closed manually operableswitch means of an operator control station, a second pair of contactterminals to be interconnected by normally open manually operable switchmeans of an operator control station, and a third pair of contactterminals to be continuously interconnected to permit energization ofsaid drive means, the opening of the circuit across said first pair ofcontact terminals resulting in the de-energization of said drive meansand the closing of the circuit across said second pair of contactterminals resulting in the energization of said operating drive means,the improvement comprising: a combination connector duplicating andoperator control station unit having input connector means with a first,second and a third pair of contact terminals which can be respectivelyremovably connected across said first, second and third pair of contactterminals of said main connector means, and output connector means witha first, second and third pair of contact terminals for respectivelymaking connection to the contact terminals of an input connector meansassociated with circuit completing means to be connected thereto, atleast one normally closed manually operable switch means and circuitconnecting means connecting the corresponding first and second pair ofcontact terminals of said input and output connector means together withsaid normally closed manually operable switch means connected in seriesbetween one of the corresponding contact terminals of said first pair ofcontact terminals of said input and output connector means and saidnormally open manually operable switch means connected in series betweenone of the corresponding contact terminals of said second pair ofcontact terminals of said input and output connector means, and meansshort circuiting said third pair of contact terminals of said inputconnector means; a terminal circuit completing unit having inputconnector means with contact terminals which can be mistakenly removablyconnected with said main connector means and is removably connectable tocontact terminals of said output connector means of said combinationconnector duplicating and operator control station unit, and means forrespectively electrically short circuiting only said first and secondpair of contact terminals of said output connector means of saidcombination connector duplicating and operating control station unit sosaid third pair of contact ter- 17;. minals of said main connector meanswill remain unconnected if said circuit completing unit is mistakenlydirectly connected to said main connector means, and circuit-formingmeans connected to the contact terminals of the last mentioned inputconnector necessary for completing a circuit where said normally openand normally closed manually operable switch means are respectivelyelectrically connected across said first and second contact terminals ofsaid main connector means.

9. The machine of claim 8 wherein said terminal circuit completing unitis a dummy unit devoid of any manually operable switch means andcontaining only means electrically short circuiting said first andsecond pair of contact terminals of said output connector means of saidcombination connector duplicating and operating control station unit.

10. The machine of claim 8 wherein said terminal circuit completingunitconstitutes a second operator control station unit having a normallyclosed manually operable switch means coupled across said first pair ofcontact tenninals of said output connector means of said combinationconnectorduplicating and operator control station unit.

11. The machine of claim 8 herewith said input connector means of saidcombination connector duplicating and operator control station unit isdirectly physically and electrically removably connected to said mainconnector means.

12. The machine of claim 8 wherein thereis provided between said mainconnector means and said combination connector duplicating and operatorcontrol station unit an intervening connector duplicating unit havinginput connector means having is first, second and third pair of contactterminals respectively connected to said first, second and third pair ofcontact terminals of said main connector means respectively having afirst, second and third pair of contact terminals: the input connectormeans of said combination connector duplicating and operator controlstation unit having its first, second and third pair of contactterminals respectively pled across said first pair of contact terminalsof said input connector means of the second operator control stationunit circuit-forming means in said intervening connector duplicatingunit which connect said first and second pair of contact terminals ofsaid first and second output connector means of said interveningconnector duplicating unit respectively between said first and secondpair of contact terminals of said main connector means, and said thirdpair of contact terminals of said first and second output connectormeans of said intervening connector duplicating unit respectively inparallel with one another and with said third pair of contact terminalsof said main connector means.

I I I! l

1. In a machine which has a work producing portion movable by anoperating drive means from a remote starting position, where an operatoris relatively safe, to a work producing position where it can injure anoperator in the vicinity thereof, and is then movable back to saidstarting position, said machine including main electrical connectormeans including at least a first pair of contact terminals to beinterconnected by manually operable switch means of an operator controlstation, the opening or closing of the circuit across said pair ofcontact terminals resulting in either the energization ofde-energization of said operating drive means, the improvementcomprising: a first connector duplication unit for enabling selectivelythe installation of one or more operator control stations includingmanually operable switch means to be connected in series between saidfirst pair of contact terminals of said main connector means, said firstconnector duplicating unit including first electrical connector meanscomplementary and removably connected to said main electrical connectormeans of the machine, and second electrical connector means forremovably receiving complementary electrical connector means of circuitcompleting means; a first operator control station having manuallyoperable switch means; and circuit completing means including firstelectrical connector means complementary and removably connected to saidsecond electrical connector means of said first connector duplicationunit; said first connector duplicating unit and said circuit completingmeans including circuit forming means for connecting said manuallyoperable switch means of said first operator control station and anysimilar manually operable switch means which may be present in saidcircuit completing means in series between said first pair of contactterminals of said main electrical connector means.
 2. The machine ofclaim 1 wherein at least part of said circuit completing means includesa second operator station with manually operable switch means connectedin series with said manually operable switch means of said firstoperator control station.
 3. The machine of claim 1 wherein said firstconnector duplicating unit includes, as an integral part thereof, saidfirst operator control station including said manually operable switchmeans.
 4. The machine of claims 1 wherein said first circuit completingmeans is a terminal circuit completing unit providing a continuouscircuit connected in series with said manually operable switch means ofsaid operator control station.
 5. The machine of claim 1 wherein saidfirst connector duplicating unit includes third electrical connectormeans for removably receiving complementary electrical connector meansof a circuit completing means, said first operator control stationforming a separate unit having first electrical connector meanscomplementary and removably connected to said third electrical connectormeans of said first connector duplicating unit, said manually operableswitch means of said first operator control station being electricallyconnected through said first electrical connector means thereof to saidcircuit-forming means of said first connector duplicating unit.
 6. Themachine of claim 2 wherein said second operator control station formpart of said circuit completing means and constitutes a connectorduplicating unit by including second electrical connector means forremovably receiving complementary electrical connector means associatedwith a terminal circuit completing unit and a terminal circuitcompleting unit forming part of said circuit completing means and havingassociated electrical connector means complementary and removablyconnected to said second electrical connector means of said secondoperator control station,and circuit forming means in said terminalcircuit completing unit and second operator control station completingconnections which connect said manually operable switch means of saidfirst and second operator control stations in series between said pairor contact terminals of said main electrical connector means.
 7. In amachine which has a work producing portion movable by an operating drivemeans from a remote starting position, where an operator is relativelysafe, to a work producing position where it can injure an operator inthe vicinity thereof, and is then movable back to said startingposition, said machine including main electrical connector means forremovably receiving complementary connector means of an external circuitcompleting means and including at least a first pair of contactterminals to be interconnected by manually operable switch means of anoperator control station, the opening or closing of a circuit acrosssaid pair of contact terminals resulting in the energization orde-energization of said operating drive means, the improvementcomprising: a first connector duplicating unit for enabling selectivelythe installation of a number of operator control stations respectivelyincluding manually operable switch means to be connected in seriesbetween said first pair of contact terminals of said main electricalconnector means, said first connector duplicating unit including firstelectrical connector means removably connected to said main electricalconnector means and having a first pair of contact terminal engagingsaid first pair of contact terminals of said main electrical connectormeans, and second electrical connector means for removably receivingcomplementary electrical connector means of circuit completing meanswhich provides a continuous interconnection between said first pair ofcontact terminals of said second electrical connector means of the firstconnector duplicating unit or an operator control which has manuallyoperable switch means to be connected between said first pair of contactterminals of said second electrical connector means of said firstconnector duplicating unit; a first operator control station includingmanually operable switch means having one terminal connected to one ofsaid first electrical connector means of said first connectorduplicating unit, means connecting the other terminal of said manuallyoperable switch means of said first operator control station to one ofsaid pair of contact terminals of said second electrical connector meansof said first connector duplicating unit, means within said firstconnector duplicating unit which connects the other of said pair ofcontact terminals of said second electrical connector means of saidfirst connector duplicating unit to the other contact terminal of saidfirst pair of contact terminals of said first electrical connector meansof said first connector duplicating unit; and circuit completing meanshaving electrical connector means with a pair of contact terminalsremovably connected to said pair of contact terminals of said secondelectrical connector means of Said first connector duplicating unit andcircuit completing means connected to said pair of contact terminals ofsaid electrical connector means thereof for completing a circuit whichconnects said manually operable switch means of said first operatorcontrol station across said first pair of terminals of said mainelectrical connector means.
 8. In a machine which has a work producingportion movable by drive means from a remote starting position, where anoperator is relatively safe, to a work producing position where it caninjure an operator in the vicinity thereof; and is then movable back tosaid starting position, said machine including main connector means forremovably receiving complementary connector means of an external circuitcompleting means and including at least a first pair of contactterminals to be interconnected by normally closed manually operableswitch means of an operator control station, a second pair of contactterminals to be interconnected by normally open manually operable switchmeans of an operator control station, and a third pair of contactterminals to be continuously interconnected to permit energization ofsaid drive means, the opening of the circuit across said first pair ofcontact terminals resulting in the de-energization of said drive meansand the closing of the circuit across said second pair of contactterminals resulting in the energization of said operating drive means,the improvement comprising: a combination connector duplicating andoperator control station unit having input connector means with a first,second and a third pair of contact terminals which can be respectivelyremovably connected across said first, second and third pair of contactterminals of said main connector means, and output connector means witha first, second and third pair of contact terminals for respectivelymaking connection to the contact terminals of an input connector meansassociated with circuit completing means to be connected thereto, atleast one normally closed manually operable switch means and circuitconnecting means connecting the corresponding first and second pair ofcontact terminals of said input and output connector means together withsaid normally closed manually operable switch means connected in seriesbetween one of the corresponding contact terminals of said first pair ofcontact terminals of said input and output connector means and saidnormally open manually operable switch means connected in series betweenone of the corresponding contact terminals of said second pair ofcontact terminals of said input and output connector means, and meansshort circuiting said third pair of contact terminals of said inputconnector means; a terminal circuit completing unit having inputconnector means with contact terminals which can be mistakenly removablyconnected with said main connector means and is removably connectable tocontact terminals of said output connector means of said combinationconnector duplicating and operator control station unit, and means forrespectively electrically short circuiting only said first and secondpair of contact terminals of said output connector means of saidcombination connector duplicating and operating control station unit sosaid third pair of contact terminals of said main connector means willremain unconnected if said circuit completing unit is mistakenlydirectly connected to said main connector means, and circuit-formingmeans connected to the contact terminals of the last mentioned inputconnector necessary for completing a circuit where said normally openand normally closed manually operable switch means are respectivelyelectrically connected across said first and second contact terminals ofsaid main connector means.
 9. The machine of claim 8 wherein saidterminal circuit completing unit is a dummy unit devoid of any manuallyoperable switch means and containing only means electrically shortcircuiting said first and second pair of contact terminals of saidoutput connector meaNs of said combination connector duplicating andoperating control station unit.
 10. The machine of claim 8 wherein saidterminal circuit completing unit constitutes a second operator controlstation unit having a normally closed manually operable switch meanscoupled across said first pair of contact terminals of said outputconnector means of said combination connector duplicating and operatorcontrol station unit.
 11. The machine of claim 8 herewith said inputconnector means of said combination connector duplicating and operatorcontrol station unit is directly physically and electrically removablyconnected to said main connector means.
 12. The machine of claim 8wherein there is provided between said main connector means and saidcombination connector duplicating and operator control station unit anintervening connector duplicating unit having input connector meanshaving is first, second and third pair of contact terminals respectivelyconnected to said first, second and third pair of contact terminals ofsaid main connector means respectively having a first, second and thirdpair of contact terminals: the input connector means of said combinationconnector duplicating and operator control station unit having itsfirst, second and third pair of contact terminals respectively removablyconnected with said first, second and third pair of contact terminalmeans of said first output connector means of said intervening connectorduplicating unit, and a second operator control station unit havinginput connector means with first, second and third pair of contactterminals respectively removably making contact with said first,secondand third pair of contact terminals of said second output connectormeans of said intervening connector duplicating unit, and at leastnormally closed manually operable switch means coupled across said firstpair of contact terminals of said input connector means of the secondoperator control station unit circuit-forming means in said interveningconnector duplicating unit which connect said first and second pair ofcontact terminals of said first and second output connector means ofsaid intervening connector duplicating unit respectively between saidfirst and second pair of contact terminals of said main connector means,and said third pair of contact terminals of said first and second outputconnector means of said intervening connector duplicating unitrespectively in parallel with one another and with said third pair ofcontact terminals of said main connector means.